1. Field of the Invention
The invention relates to an electronic load apparatus, and more particularly to an electronic load for simulating electrical characteristics of a semiconductor element by utilizing at two slope generating circuits.
2. Description of the Related Art
An electronic load apparatus is a fundamental and crucial equipment in a development and manufacturing of a power supply device. The electronic load apparatus is capable of replacing any circuit combinations of resistors and batteries to simulate a load at an output of a power supply device, so as to be applied in related research and development, quality control and production tests.
Electronic loads of different operating modes including constant current mode, constant voltage mode, constant power mode and constant resistance mode have been provided by the prior art with respect to resistance, battery and circuit aspects. However, due to electrical characteristics of semiconductor elements that have a conducting state voltage, the above conventional electronic loads are inappropriate for simulations of semiconductor elements.
Taking a light-emitting diode (LED) for example, the LED is inactive when a voltage fed to the LED is smaller than a predetermined conducting state voltage, and it only becomes active (i.e., lit up) when the voltage fed to the LED is greater than the conducting state voltage. In current simulations of electrical characteristics of LEDs, a simple constant resistance mode is generally utilized in simulating an LED. As stated previously, not only the conventional electronic load operating at a constant resistance mode but also the conventional electronic load operating at a constant current mode, a constant voltage mode and a constant power mode are incapable of accurately achieving simulations of electrical characteristics of LEDs.
Another conventional electronic load for simulating an LED with respect to characteristics of the LED is also proposed. Although this conventional electronic load also simulates with a resistance mode, a non-linear voltage applied to the LED is directly deducted before proceeding to the resistance operating mode. The reason for such measure is that an important electrical characteristic of semiconductor elements is in fact purposely neglected, meaning that inaccurate results are rendered by this conventional electronic load. Yet, under precision demands of semiconductor elements, this conventional electronic load fails to meet manufacturer requirements.